1. Field of the Invention
The present invention relates to attic and roof ventilation systems and more particularly to providing ventilation to sloped roof structures having metal roofs.
2. Description of the Background
The practice of ventilating sloped roofs structures by creating a vent opening along the roof ridge is well known in the construction industry. A vent slot is created during construction by leaving a gap between the roof deck and the roof beam running along the ridge extending essentially the length of the roof. The air is vented from the structure by convection airflow and by suction from wind blowing across the roof. The vent slot must be covered to keep water, dirt and pests out of the structure. The required covering in turn diminishes the air flow from under the roof. Typically, in metal roof installations, a ridge panel or cap is connected to the top row of roof panels atop the ridge slot with a closure strip or mastic disposed between the ridge panel and the roof panels. However, covering the ridge slot prevents the desired ventilation from under the roof. Another well known method in the construction industry involves installing ventilators atop the ridge slot. However, that ventilator installation requires additional labor which is very effective expensive.
Powered fan ventilation is well-known for buildings. However, the power required to operate the fan in such devices requires an additional power outlet installation for the roof. Also, ventilating the building in this manner may be cost prohibitive because of the energy cost, and there is potential fire hazard associated with unattended electrical appliance operation. Passive, convection type vents provide an economical and safe alternative to powered fans for ventilating buildings. In buildings having peaked roofs, the natural flow of air within the building rises to the uppermost area, which is typically
adjacent the peak of the roof. Several attempts have been made to overcome the problems of passive ventilating the metal roofs. U.S. Pat. No. 5,561,953 discloses a contoured ventilation system for metal roofs that requires a sheet overlaying the decking wherein the sheet has a plurality of projections projecting away from the decking, and a strip having a surface including a plurality of recesses shaped to match the projections of the sheet. The requirement of having such a sheet adds to the expense and further degrades the ventilation efficiency. U.S. Pat. No. 5,826,383 describes a roof closure vent system in which the ridge closure vent requires a closure member having lateral perforations for air to pass through, and a mesh mat adjacent to the closure member. Ventilation through a perforated members reduces ventilation efficiency by reducing the available vent volume, and further the perforated member is subject to degradation over time. A roof ventilating system for frame construction building is described in U.S. Pat. No. 5,924,925 that discloses a vent cover assembly in which flashing strips are installed to the vent cover. The vent cover assembly is mounted over the vent opening. Clearly, additional weight of the vent cover and flashing strips reduces passive ventilation efficiency of the system.
Therefore, it is an objective of this invention to provide an effective passive ventilation system for metal roofs without any moving parts that adversely impact ventilation efficiency. Another objective of the invention is to eliminate use of any porous sheet or use of the like material that may degrade over time and that adversely impacts ventilation efficiency. It is yet another objective of the invention to provide a safe and economic installation of the metal roof on building structures.